JPH0780933A - Production of flanged resin lining steel pipe - Google Patents

Abstract

PURPOSE:To obtain sufficient strength and corrosion resistance while preventing the peel between both lining layers accompanied by thermal shrinkage by preforming a recessed part in which a part of a resin flows to the inner surface of the end part of a main body lining layer when a flange lining layer is formed by injection molding. CONSTITUTION:An adhesive is applied to the inner surface of the steel pipe main body 11 of a flanged steel pipe 1 and a synthetic resin pipe is inserted in the steel pipe main body 11 to be integrated with the main body 11. By this method, a main lining layer 3b is formed excepting the end part 14 of the steel pipe main pipe 11 in the vicinity of a flange 12. A recessed hole 32 is formed to the inner peripheral surface of the end part of the main body lining layer 3b as a recessed part. Next, an injection mold 6 having an axis same to the pipe axis of the steel pipe main body 11 is mounted on the end part of the flanged steel pipe 1 and a core mold 5 is mated with the end part of the main body lining layer 3b. A molten resin is injected into a cavity 62 from a resin injection port 61 to form a flange lining layer 7. At this time, the resin entering the recessed hole 32 acts as an anchor.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a resin lining steel pipe with a flange by lining a resin from the inner surface of the flanged steel pipe having a flange for joining to the pipe end to the pipe end.

[0002]

2. Description of the Related Art A flanged steel pipe used as a pipe material having a flange integrally provided at the end of a steel pipe body is used, for example, in order to improve its corrosion resistance.
As shown in Japanese Patent Laid-Open No. 5-31091, there is a steel pipe main body in which a resin is lined from the inner surface to the pipe end flange surface.

When such a resin-lined steel pipe with a flange is manufactured, if there is a portion where the resin does not exist from the inner surface of the pipe end portion to the flange surface, corrosion may proceed from that portion during use. Therefore, in manufacturing, it is necessary to form the lining layer so that the resin exists without interruption not only on the inner surface of the steel pipe but also from the inner surface of the pipe end portion to the flange surface.

Therefore, conventionally, after a resin pipe longer than the steel pipe is inserted into the steel pipe to line the inner surface of the steel pipe, the end portion of the resin pipe is turned back along the pipe end flange surface of the steel pipe ( For example, see Japanese Patent Publication No. 56-37889), or after lining the inner surface of the steel pipe with a resin pipe shorter than the steel pipe, one end of another resin short pipe is adhered to the end of the resin pipe with an adhesive. There is a method of lining the resin without interruption to the pipe end flange surface by projecting the other end side from the pipe end part by a predetermined amount and turning the protruding part of this short pipe back along the pipe end flange surface. Has been done.

[0005] However, the conventional manufacturing method using the above-described flange-returning process is made of the resin pipe for the pipe end lining or the end of the resin pipe for the inner surface lining inserted into the flanged steel pipe. After heating and softening the end portion of the short pipe, the portion is subjected to the flange-back processing as described above and brought into close contact with the pipe end flange surface. Therefore, among thermoplastic resins, it is applicable to resins having relatively good elongation and excellent workability such as hard vinyl chloride resin, but resins called engineering plastics that have a high melting point and are difficult to extend, such as polyvinylidene fluoride. (PVD
F), polyphenylene sulfide (PPS), polyether ether ketone (PEEK) and other resins cannot be applied or are extremely difficult. Further, in the case of a resin that is difficult to adhere such as a fluororesin (for example, PVDF), an adhesive cannot be used to join the resin pipe for the inner surface lining and the resin short pipe for the pipe end lining, The use of resin short tubes will be restricted.

Therefore, in the conventional case, when lining the portion of the flanged steel pipe from the inner surface of the steel pipe body to the pipe end flange surface with a resin, only a resin that can be used for the above-mentioned flange-back processing and an adhesive is used. However, there is a problem in that the type of lining resin and the product performance are limited accordingly.

[0007]

Therefore, the applicant of the present invention has previously proposed the following method for producing a flanged resin-lined steel pipe (Japanese Patent Application No. 5-75759).
issue). That is, this manufacturing method, as shown in FIG.
First, the flanged steel pipe 100 in which the flange 102 is integrally provided at the end of the steel pipe body 101 is prepared. And
After the adhesive 103 is applied to the inner surface of the steel pipe body 101 of the flanged steel pipe 100, a synthetic resin pipe 104, which is slightly shorter than the steel pipe body 101, is inserted into the steel pipe body 101, and the steel pipe body 101 and the synthetic resin pipe 104 are bonded together with the adhesive 103. The tube 104 and the tube 104 are bonded and integrated to form a main body lining layer. Next,
The steel pipe body 10 is so fitted that a core mold 105 having substantially the same diameter as the inner diameter of the synthetic resin pipe 104 is fitted to the tip portion of the synthetic resin pipe 104.
1 and the injection molding die 106 is set at the end of the flanged steel pipe 100. And FIG.
As shown in FIG. 3, a resin heated and melted at a predetermined temperature is injected into the cavity 107 and cooled and solidified, so that the synthetic resin pipe 104 is integrally connected with the synthetic resin pipe 104 by injection molding from the inner surface of the end of the steel pipe main body 101 to the surface of the flange 102. The flange lining layer 108 is formed.

According to this method, the end portion of the resin pipe for the inner surface lining is flanged, or a short pipe made of resin is joined to the resin pipe with an adhesive, and then the end portion of the short pipe is joined. There is no need to process the collar. Therefore, for example, P
Like engineering plastics such as PS, it cannot be used as a lining material because it has excellent physical properties in terms of dimensional stability, heat resistance, chemical resistance, etc. It is also possible to use other resins, and thus it is possible to manufacture various types of flanged resin-lined steel pipes that are excellent in performance by taking advantage of the physical properties of the resin.

However, the above-mentioned manufacturing method proposed by the present applicant has the following problems. That is, since the flange lining layer is formed by injecting molten resin, the synthetic resin pipe 104
The flange lining layer 108 and the flange lining layer 108 are joined together by heat fusion at the interface, but the strength of the heat fusion portion is weak and peeling occurs at the interface between the two due to thermal expansion and contraction of the resin. There is a possibility that the anticorrosion effect may not be exhibited.

The present invention addresses such a problem, and the flanges are not required to be subjected to a flange-back process or to use an adhesive for joining the inner surface lining resin and the pipe end lining resin. The resin can be lined without interruption from the inner surface of the attached steel pipe to the pipe end flange surface, and thus various resins with excellent physical properties can be used as the lining material for the flange steel pipe, as well as the main body lining layer and the flange. An object of the present invention is to provide a method for producing a flanged resin-lined steel pipe, which has excellent jointability with the lining layer and does not cause peeling or the like at the interface between the synthetic resin pipe and the flange lining layer due to expansion or contraction.

[0011]

In order to achieve the above object, a method for manufacturing a resin-lined steel pipe with a flange according to the present invention is a steel pipe main body of a flanged steel pipe in which a flange is integrally provided at an end portion of the steel pipe main body. After inserting a shorter synthetic resin pipe into the steel pipe main body, and forming a main body lining layer in a portion near the flange except the end of the steel pipe main body by integrating the synthetic resin pipe and the steel pipe main body with an adhesive, A method for producing a resin lining steel pipe with a flange, wherein a continuous flange lining layer is formed from a flange surface to an end of the main body lining layer by injection molding a resin, wherein the flange lining layer is formed by injection molding. A concave portion into which a part of the above is introduced is formed in advance on the inner surface of the end portion of the main body lining layer.

In the above structure, as a method of forming the recess, a recess is previously formed in the synthetic resin pipe, and the synthetic resin pipe is inserted into the steel pipe main body to be integrated with the steel pipe main body. There is a method of inserting the steel pipe body into the steel pipe body and integrating it with the steel pipe body, and then forming a recess at the end of the synthetic resin pipe using a cutting tool such as a grinder. Examples of the concave portion include a concave hole and a concave groove, and it is preferable to provide the concave portion continuously or radially on the same circumference.

As the resin forming the lining layer, vinyl chloride resin, polyvinylidene fluoride (PVDF), polyphenylene sulfide (PPS), polyether ether ketone (PEEK), fluororesin (eg PV
DF) and the like. Further, the flanged steel pipe includes not only those in which the flanges are provided at both ends of the steel pipe body, but also those in which the flange is provided only at one end of the steel pipe body.

[0014]

According to the above construction, the synthetic resin pipe shorter than the steel pipe main body is inserted into the steel pipe main body of the flanged steel pipe, and the synthetic resin pipe is integrated with an adhesive to remove the end of the steel pipe main body near the flange. After forming the main body lining layer on the inner peripheral surface and forming the concave portion at the end of the main body lining layer,
The flange lining layer is formed by separately lining the resin from the unrunning portion of the steel pipe body to the flange surface of the pipe end by injection molding, but a recess is formed at the end of the body lining layer. Therefore, the recess is filled with a part of the resin that forms the injected flange lining layer.

Therefore, when cooled and solidified, not only the main body lining layer and the flange lining layer are integrated by fusion bonding at the interface by part of the flange running layer flowing into the recess acting as an anchor. Mechanically integrated.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to the drawings showing the embodiments thereof. 1 and 2 show a first embodiment of a method for manufacturing a resin lining steel pipe with a flange according to the present invention in the order of steps. That is, the method of manufacturing the resin lining steel pipe with a flange is performed in the following process order.

As shown in FIG. 1, first, the steel pipe body 1
A flanged steel pipe 1 in which flanges 12 and 12 are integrally provided at both ends of 1 is prepared, and an adhesive 13 is applied to an inner surface of a steel pipe body 11 of the flanged steel pipe 1. The synthetic resin pipe 3a is inserted in the direction of the arrow and integrated with the steel pipe body 11 via the adhesive 13. In addition, synthetic resin pipe 3
a is slightly shorter than the steel pipe body 11,
Small holes 31 penetrating from the inner surface to the outer surface are radially provided at the end portion on the same circumference.

Therefore, the synthetic resin pipe 3a is bonded and integrated with the steel pipe main body 11 to form the main body lining layer 3b except for the steel pipe main body end portion 14 near the flange 12 as shown in FIG. 2 (a). At the same time, a concave hole 32 as a concave portion is formed on the inner peripheral surface of the end portion of the main body lining layer 3b. As shown in FIG. 2 (b), an injection molding die (flange type) 6 having the same axis as the pipe axis of the steel pipe body 11 is attached to the end of the flanged steel pipe 1, and the core die 5 is lining the body. Fit on the end of layer 3b.

Molten resin is injected from the resin injection port 61 into the cavity 62 to form the flange lining layer 7 as shown in FIG. 2C. If necessary, after injection molding, further cutting is performed to remove burrs and the like. As described above, in the method for manufacturing the resin lining steel pipe with a flange, the molten resin forming the bulging lining layer 7 at the time of injection molding enters the concave hole 32 at the time of injection molding and is cooled and solidified as it is. At the interface with the lining layer 3b, the resin is integrated with the main body lining layer 3b by fusion, and the resin in the recessed holes 32 of the flange lining layer 7 acts as an anchor to mechanically also main body lining layer 3b. Is integrated with.

Therefore, the flange lining layer 7 and the main body lining layer 3b are firmly integrated, and peeling at the interface due to thermal expansion and contraction does not occur, so that the flanged resin lining steel pipe is always provided with sufficient strength and corrosion resistance. Can be provided. Of course, after the main body lining layer 3b is formed, the flange lining layer 7 is separately formed by injection molding from the inner surface of the unlined portion of the steel pipe body 11 to the surface of the flange 12, so that the pipe from the inner surface of the steel pipe body 11 is formed. The resin lining layer is formed without interruption over the surface of the flange 12 at the end. Therefore,
There is no need to rebar the end of the resin pipe for the inner lining of the steel pipe as in the past, or to bond the resin short pipe to the resin pipe with an adhesive and then rebar the end. However, the resin is surely lined from the inner surface of the steel pipe body 11 to the surface of the flange 12 at the pipe end, and the flanged resin is used even if a resin with a high melting point that is difficult to extend is difficult to be applied to the collar and the use of an adhesive. It becomes possible to manufacture lining steel pipes.

In other words, polyvinylidene fluoride (PVDF) and polyphenylene sulfide (PP) are used as the lining material for the resin lining steel pipe with flange.
Resins having excellent physical properties such as S) and polyether ether ketone (PEEK) can be used, and products having excellent performance (for example, dimensional stability) can be obtained.

FIG. 3 shows a second embodiment of a method of manufacturing a resin-lined steel pipe with a flange according to the present invention in the order of steps. In this embodiment, a synthetic resin pipe (not shown) having a groove formed on the inner peripheral surface of the end is inserted into the steel pipe main body 11 and integrated with an adhesive as in the above-described embodiment. )
As shown in FIG. 3, the main body lining layer 3 b having the groove 33 as a recess at the end is formed in the steel pipe main body 11. Then, as shown in FIG. 3 (b), an injection molding die (flange die) 6 having the same axis as the pipe axis of the steel pipe body 11 is attached to the end of the flanged steel pipe 1, and the core die 5 is attached. After fitting to the end of the main body lining layer 3b, the resin injection port 6
The molten resin is injected into the cavity 62 from No. 1, and as shown in FIG.
The flange lining layer 7 can be formed as shown in (c).

According to the method of this embodiment, as in the case of the first embodiment, the molten resin forming the bulging lining layer 7 at the time of injection molding enters the groove 33 and is cooled and solidified as it is. Body lining layer 3
It is integrated with the main body lining layer 3b by fusion bonding at the interface with b, and the resin in the portion of the flange lining layer 7 that has entered the concave groove 33 acts as an anchor and is also mechanically integrated with the main body lining layer 3b. Be converted.

Therefore, the flange lining layer 7 and the main body lining layer 3b are firmly integrated with each other, and thermal expansion and contraction do not cause peeling at the interface, so that the flanged resin lining steel pipe always has sufficient strength and corrosion resistance. Can be provided.

[0025]

As described above, according to the method for producing a resin lining steel pipe with a flange according to the present invention, the method for producing a resin lining steel pipe with a flange is the same as the method for producing a resin lining steel pipe with a flange previously proposed by the applicant. When lining the part from the inner surface to the pipe end flange surface, the inner surface of the flanged steel pipe is lined with resin, and then the resin lining layer is formed by injection molding on the pipe end of the steel pipe. It is not necessary to perform end-reverse processing on the end of the pipe, or to join the short pipe made of resin to the resin pipe via an adhesive and then perform end-reverse processing on the end of the short pipe.

Therefore, in the case of manufacturing this kind of flanged resin-lined steel pipe, it has excellent physical properties in terms of dimensional stability, heat resistance, chemical resistance and the like, such as engineering plastics such as PPS mentioned above. However, it is possible to use the resin that could not be used as the lining material because it was difficult to process the flange and use the adhesive, and by extension, various flanged resin-lined steel pipes with excellent performance utilizing the physical properties of the resin. Can be manufactured.

Moreover, the main body lining layer and the flange lining layer are not only integrated at the interface by fusion, but also a part of the resin forming the flange lining layer is fitted into the recess provided in the main body lining layer. Since it is mechanically joined and integrated by fitting it, there is no peeling at the interface between the main body lining layer and the flange lining layer due to thermal expansion and contraction, and a resin lining with a flange that has sufficient strength and corrosion resistance at all times. Steel pipe can be provided.

[Brief description of drawings]

FIG. 1 is a view showing a first embodiment of a method for manufacturing a resin-lined steel pipe with a flange according to the present invention, which is a cross-sectional view showing a state before inserting a synthetic resin pipe as a main body lining layer into a steel pipe main body. Is.

2A and 2B are views for explaining the first embodiment in the order of steps, in which FIG. 2A is a sectional view showing a state in which a main body lining layer is formed in a steel pipe main body, and FIG. Sectional drawing showing the state that the mold is set, the same figure (c)
FIG. 6 is a cross-sectional view showing a state where resin is injected into the cavity.

FIG. 3 is a view for explaining the second embodiment of the method for manufacturing a flanged resin-lined steel pipe according to the present invention, in which FIG. 3 (a) shows a state in which a main body lining layer is formed inside the steel pipe main body. Sectional view, (b) is a sectional view showing a state in which an injection mold is set on the flange, (c).
FIG. 6 is a cross-sectional view showing a state where resin is injected into the cavity.

FIG. 4 is a cross-sectional view showing a state before injection molding in the previously proposed method for manufacturing a flanged resin-lined steel pipe.

5 is a cross-sectional view showing the state after injection in FIG.

[Explanation of Codes] 1 Steel pipe with flange 7 Flange lining layer 3a Synthetic resin pipe 3b Main body lining layer 11 Steel pipe main body 12 Flange 13 Adhesive 14 Steel pipe main body end portion near the flange 32 Recessed hole (recessed portion) 33 Recessed groove (recessed portion)

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display location F16L 23/028

Claims (1)

[Claims] 1. A flanged steel pipe having a flange integrally provided at an end portion of the steel pipe body, wherein a synthetic resin pipe shorter than the steel pipe body is inserted into the steel pipe body and the synthetic resin pipe is bonded to the synthetic resin pipe via an adhesive. After forming the main body lining layer on the part near the flange except the end of the steel pipe main body by integrating with the steel pipe main body, the resin is injection molded to form a continuous flange lining layer from the flange surface to the end of the main body lining layer. A method of manufacturing a resin lining steel pipe with a flange to be formed, wherein when a flange lining layer is formed by injection molding, a recess into which a part of the resin flows is formed in advance on the inner surface of the end of the main body lining layer. A method of manufacturing a resin-lined steel pipe with a flange, which is characterized.